High-Mn Solid Welding Wire Composition for Low-Fume Cryogenic Joints

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Solution Overview

Problem

Existing welding techniques for high Mn steel materials in cryogenic environments generate excessive fumes, compromising welder safety and weld quality, while existing solid wires are prone to cracking during drawing due to their chemical composition.

Innovation Solution

A solid wire with a chemical composition optimized for gas metal arc welding, specifically within the ranges of C: 0.2% to 0.8%, Si: 0.15% to 0.9%, Mn: 17.0% to 28.0%, Ni: 0.01% to 10.0%, Cr: 0.4% to 4.0%, and Mo: 0.01% to 3.5%, with reduced impurities like B, Ti, and V, to prevent cracking and minimize fume generation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If flux cored wire is used for welding high Mn steel, then weld joint strength and low-temperature toughness can be achieved, but excessive fume is generated during welding

Engineering Contradiction:
Improveweld joint strengthVSAvoidfume generation
Core Design Contradiction:
StrengthVSObject-generated harmful factors

Solution Approach 1:

The patent changes the chemical composition parameters of the welding wire by strictly limiting boron content to 0.0006% or less and controlling carbide-forming elements (Ti: 0.03% or less, V: 0.03% or less, Nb: 0.03% or less), while optimizing C (0.22-0.75%), Si (0.10-0.85%), Mn (18.0-30.0%), and other alloying elements. This parameter optimization prevents excessive carbide formation that generates fume, while maintaining weld joint strength of 400 MPa or more and low-temperature toughness with absorbed energy of 28 J or more at -196°C.

Inventive Principle:
Principle #35Parameter changes

2Object-generated harmful factors

If solid wire with high Mn content is used, then fume generation is reduced, but cracks occur during wire drawing process

Engineering Contradiction:
Improvefume generationVSAvoidwire drawing process
Core Design Contradiction:
Object-generated harmful factorsVSEase of manufacture

Solution Approach 1:

The patent optimizes the chemical composition parameters to prevent cracks during wire drawing. Specifically, boron is controlled to 0.0006% or less to prevent brittle boride formation, while carbide-forming elements (Ti, V, Nb) are limited to 0.03% or less each. The carbon content is optimized to 0.22-0.75% and silicon to 0.10-0.85%, creating a composition that maintains adequate ductility for wire drawing while preserving the high Mn (18.0-30.0%) content needed for low-temperature toughness and strength.

Inventive Principle:
Principle #35Parameter changes

3Ease of operation

If conventional welding materials are used for high Mn steel, then welding can be performed, but weld quality and consistency are insufficient

Engineering Contradiction:
Improvewelding processabilityVSAvoidweld quality
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent establishes precise chemical composition ranges to ensure consistent weld quality: C (0.22-0.75%), Si (0.10-0.85%), Mn (18.0-30.0%), P (0.03% or less), S (0.03% or less), Ni (0.01-10.00%), Cr (0.40-4.00%), Mo (0.01-3.50%), with boron ≤0.0006% and carbide-forming elements (Ti, V, Nb) each ≤0.03%. This precise parameter control ensures reproducible weld metal properties including yield strength ≥400 MPa, tensile strength ≥470 MPa, and absorbed energy ≥28 J at -196°C, while maintaining good weldability and appearance.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS20210323101A1Solid wire for gas metal arc welding
Publication Date: 2021.10.21 JFE STEEL CORP

AI summary

Provided is a solid wire for gas metal arc welding, which has a small amount of fume during welding and is suitable as a welding material for high Mn steel materials. The wire has a chemical composition containing, in mass %, C: 0.2% to 0.8%, Si: 0.15% to 0.90%, Mn: 17.0% to 28.0%, P: 0.03% or less, S: 0.03% or less, Ni: 0.01% to 10.00%, Cr: 0.4% to 4.0%, Mo: 0.01% to 3.50%, B: less than 0.0010%, and N: 0.12% or less, with the balance consisting of Fe and inevitable impurities. It may contain at least one selected from V, Ti, Nb, Cu, Al, Ca and REM, if necessary. The wire has excellent manufacturability, can significantly suppress the amount of fume generated during gas metal arc welding, and can easily manufacture a weld joint having high strength and excellent impact toughness at cryogenic temperatures.